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Immature Tough Guy
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5,671 Posts
Discussion Starter #1 (Edited)
Stock and Aftermarket Springs

If you are interested in dropping your car with lowering springs, at least know what your stock rates are, and those of the aftermarket product you are looking to get. Spring rates measure how "stiff" the springs are, measured in lbs/inch. Drop is how much lower your car will be compared to stock ride height.

The chart below was posted by chickracer over 2 years ago and shows the stock b15 spring rates. To the best of my knowledge, the 1.8s still uses the same rates as the GXE, and I don't think the SE-R or SpecV rates have changed for '04 or '05.

***The chart link is gone, so I only know some of the rates from memory***


154F/247R - SpecV (all years)
134F/212R - SE-R (5spd/auto) and SE (w/PP)
134F/190R - 2.5S/LE/SE (w/o PP)
123F/190R - 1.8S/GXE/XE



Here are the spring rates and (drop) of the most popular aftermarket lowering springs. Understand that you really don't want to drop too much, and the rates should be higher than stock to compensate for less wheel travel:


180F/300R (1.2"F/1.0"R) Eibach Pro-Kit (gen2 #6362.140)
200F/333R (1.6"F/1.6"R) Eibach Sportline (gen2 #EIB4.6263)

168F/258R (1.3"F/1.1"R) Tanabe NF210
174F/258R (1.8"F/1.8"R) Tanabe DF210
207F/314R (1.3"F/1.1"R) Tanabe GF210

170F/270R (1.3"F/1.1"R) Tein S-Tech
154F/246R (0.9"F/0.6"R) Tein H-Tech

190F/280R (1.2"F/1.0"R) Swift Sport

230F/290R (1.5"F/1.5"R) Goldline


190F/240R (1.7"F/1.5"R) Progress a.k.a Intrax

172F/274R (1.6"F/1.6"R) Vogtland

280F/230R (2.0"F/2.0"R) Megan Racing

150F/190R (2.0"F/2.0"R) Sprint

???F/???R (1.5"F/1.5"R) B&G

???F/???R (1.5"F/1.4"R) H&R



I would stay away from Sprint because the drop is too low and rates too soft. Also, you really should know the rates of the lowering spring you are putting on your car, not knowing the spring rate is like not knowing the width of a tire. You need to know the rates to setup the suspension properly!

Also, here are the numbers for the Ground Control coilover sleeves, don't bother using these on stock dampers, the rates are too high. Use with Koni Sport for best results.

375F/300R (~1.0"-2.5"F/~0.5"-2.5"R) Ground Control (interchangable front and back)



Complete Coilover Systems

For more information visit my b15 suspension writeup at:
http://www.southern-shift.com/forums/viewtopic.php?t=1001


Nismo S-tune Kit
Spring Rates: 185F/300R (progressive, meaning this is just the MAX rate)
Swappable Springs: NO
Ride Height Adjust: NO (fixed at 1.0"F/0.6"R)
Damper Type: Twin Tube Hydraulic
Damper Adjustment: NO
Upper Mounts Incl?: YES
Install Difficulty: LOW (pops right into car)
Street Price: $800

Tein Basic
Spring Rates: 336F/336R (linear)
Swappable Springs: YES (+/- 56 ft/lbs)
Ride Height Adjust: YES (1.0"-2.4"F/0.5"-2.3"R)
Damper Type: Twin Tube Hydraulic
Damper Adjustment: NO
Upper Mounts Incl?: NO
Install Difficulty: MEDIUM (reuse stock upper mounts)
Street Price: $800

Koni/Ground Control
Spring Rates: 375F/300R (linear)
Swappable Springs: YES (+/- 25 ft/lbs)
Ride Height Adjust: YES (~1.0"-2.5"F/~0.5"-2.5"R)
Damper Type: Twin Tube Hydraulic
Damper Adjustment: YES (no notches, ~2 full turns from soft to stiff)
Upper Mounts Incl?: NO
Install Difficulty: VERY HIGH (reuse stock upper mounts, front strut housing, properly install GC)
Street Price: $850

Tein SS
Spring Rates: 336F/280R (linear, some use 392R)
Swappable Springs: YES (+/- 56 ft/lbs)
Ride Height Adjust: YES (1.0"-2.4"F/0.8"-2.3"R)
Damper Type: Twin Tube Hydraulic
Damper Adjustment: YES (16 way, 32 with EDFC)
Upper Mounts Incl?: NO
Install Difficulty: MEDIUM (reuse stock upper mounts)
Street Price: $1100

KSport
Spring Rates: 392F/280R (linear)
Swappable Springs: YES (+/- 56 ft/lbs)
Ride Height Adjust: YES (~1.0"-2.5"F/~0.5"-2.5"R) (can adjust overall damper length)
Damper Type: Twin Tube Hydraulic
Damper Adjustment: YES (36 way)
Upper Mounts Incl?: YES
Install Difficulty: LOW
Street Price: $850

JIC FLT-A1
Spring Rates: 392F/280R (linear, several use 336R)
Swappable Springs: YES (+/- 56 ft/lbs)
Ride Height Adjust: YES (~1.0"-2.5"F/~0.5"-2.5"R) (can adjust overall damper length)
Damper Type: Twin Tube Nitrogen Gas
Damper Adjustment: YES (5 way)
Upper Mounts Incl?: YES (pillowball w/front camber adjustment)
Install Difficulty: LOW
Street Price: $1150

JIC FLT-A2
Spring Rates: 392F/280R (linear, several use 336R)
Swappable Springs: YES (+/- 56 ft/lbs)
Ride Height Adjust: YES (~1.0"-2.5"F/~0.5"-2.5"R) (can adjust overall damper length)
Damper Type: Mono Tube Nitrogen Gas
Damper Adjustment: YES (15 way)
Upper Mounts Incl?: YES (pillowball w/front camber adjustment)
Install Difficulty: LOW
Street Price: $1750


One quick note: Stay away from B&G coilovers. Just ask David, I believe his exact quote was "overall they were the worst things I have bought for my car and I wish I could get my money back".



Lowering your car

When it comes to lowering your car, you either do it the right way, meaning using quality parts and making sure you install them correctly, or you don't do it at all. As a general rule, no aftermarket spring alone is really designed to work well with stock shock absorbers (or dampers) over an extended period of time. Dampers are a wearable part like brake pads and tires...eventually you have to switch them out after using them with stock springs anyway. The design of our suspension does not allow a lot of drop on stock dampers, and even modest lowering will cause premature wear. How soon your dampers go depends on things like what springs you use, but also your driving style or what the road surfaces are like in your area.

The main reason stock dampers should not be paired with almost all lowering springs is wheel travel. Anytime you drop your b15 on stock dampers you will lose wheel travel and bottom out more often. A really bad example is using 2" lowering springs with stock dampers. Because the stock dampers are too long for the shorter springs, the car at rest has the shock piston almost completely compressed...to the point where you can't even push down on the car because there is no shock travel. Not only will this kill your dampers in no time, it may also cause damage to other suspension components.

It is popular to only use lowering springs because it's cheap and looks so damn good. But you cannot escape the fact that our factory shock absorbers are tuned by Nissan engineers to work specifically with the factory springs, switch only one piece out, and the car just won't work right after a while. It's like using tires that are way too small for your rims, technically they may fit, but you might damage the rims and other suspension pieces and experience ride quality issues.

Here's what Koni has to say about this:

Koni North America said:
KONIs are designed to fit standard height cars and can work with lowered cars as long as they don't bottom out internally and become damaged. Unlike some shocks, KONIs ARE NOT POSITION SENSITIVE SO THEY WILL WORK PROPERLY ANYWHERE IN THEIR STROKE RANGE PROVIDING THEY ARE NOT BOTTOMING OR TOPPING OUT. Different vehicle suspension designs have different stroke travels...
Having owned a set of Konis for four years now, I can tell you that they much stronger than the factory struts. Despite this, they did bottom out with Eibach Prokit springs which offer one of the most conservative drops on the market. This point highlights the fact that our cars have very little shock travel to begin with.

So now imagine what any lowering spring will do to the factory struts. Get the point?


Which product should I get?

Save up your money and definitely get a coilover system like Nismo S-tune or Tein Basic. They are ideal suspension setups, because the dampers and springs are matched to each other by engineers to give you the best balance between performance, ride quality and durability.

Using Koni Sport "Yellows" (which have stronger adjustable internal valving versus factory) to Ground Control sleeves is another route that has proven fairly popular for a number of users on this board. Once installed CORRECTLY (shortening the front konis, possibly relocating the front spring perch, choosing the right length and rate ERS springs, using the correct GC top hats, replacing plastic thrust bearings with metal b13 ones, revalving the konis to match the spring rates, adding external adjustability in the rear, etc.) the Koni/GC setup is arguably the BEST performance setup for the B15 Sentra.

If you want a VERY LOW drop, like 2" and still have decent ride quality, get the Tein Basic, you won't regret it. It is infinitely better than using lowering springs. If you want a slight drop, better performance, a quality ride, and an extremely easy install get the Nismo S-tune. For under $1000, these are the only two products I would personally put on my car.



Where can I get these aftermarket suspension products?

www.shox.com
www.performancenissanparts.com
www.sportcompactonly.com
www.ptuning.com


Feel free to ask any questions in this thread or PM me.
 

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M07S
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2,422 Posts
Dangling Fury said:
I had to guess on the lowering range of the JIC-FLTA2s, they are not listed on their website. What you see is an "educated guess" on my part.
I think that is right, it's 7 kg/mm front and 5 kg/mm rear, with 1 kg/mm increments AVAILABLE AT NO COST at time of purchase and $165 per spring at any time. Re-valving was something like $2xx but only really needed with big differences in spring rate. (Properly valved if you order different spring rates at the time of purchase.) The only real problem is the damper valving changes have to be sent back to Japan to get re-valved. They have no US service center.
 

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Immature Tough Guy
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5,671 Posts
Discussion Starter #8
JoelAZ said:
I think that is right, it's 7 kg/mm front and 5 kg/mm rear, with 1 kg/mm increments AVAILABLE AT NO COST at time of purchase and $165 per spring at any time. Re-valving was something like $2xx but only really needed with big differences in spring rate. (Properly valved if you order different spring rates at the time of purchase.) The only real problem is the damper valving changes have to be sent back to Japan to get re-valved. They have no US service center.
Actually, I knew that about the spring rates, I was talking about the drop range. Tein gives the minimum and maximum lowering drop on their website, and I couldn't find this info on JICs. So I just guessed that it was
~1.0"-2.5"F/~0.5"-2.5"R, a bit more range than Tein because of JICs damper length adjustment independent of the spring perch height.
 

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Registered
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4,958 Posts
This needs to be stickied, or put in the FAQ. Too many people ask about lowering their car.


I can vouch for how nice the Tanabe GF210 springs are. Even though the rates are higher than the ProKits, the ride is less bouncy, and for the most part more comfortable. (somehow) The performance of them is great, car handles a lot better. Over a year of driving on stock Spec-V struts (Florida roads are good btw) and the dampers are as good as new still.
 

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Southern Shift Racing
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2,511 Posts
Dangling Fury said:
180F/300R (1.0"F/0.6"R) Nismo S-tune Suspension Kit

336F/336R (1.0"-2.4"F/0.5"-2.3"R) Tein Basic
336F/280R (1.0"-2.4"F/0.8"-2.3"R) Tein SS

392F/280R (???"-???"F/???"-???"R) KSport (lowering range tbd)

392F/280R (~1.0"-2.5"F/~0.5"-2.5"R) JIC FLT-A2
Nismo front spring rates are actually 185. ;) The rears are correct though. :D
 

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Endless USA S13 Silvia
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3,084 Posts
i think i would say the the FLT-A2a lower more like a maximum of 3" or more even

and it would probably be a good idea to mention, as Joel said.......that you can get the 6kg/mm (336lb/in) springs at no additional cost.......i have the 6kg/mm springs on my JICs and honestly.......i think it would be too soft for track use with the 5kg/mm springs'

btw.......great post :cool:
 

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Tired...New Father
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1,693 Posts
Steve,

It's good to have you back man...I hope things are going well.

I would only make one suggestion. Including a quick reference for susp. novices...on what spring rates are and why diffecences are significant.

This is a FAQ if I've ever seen one.
 

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Endless USA S13 Silvia
Joined
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3,084 Posts
009 -2.0 SE- said:
Steve,

It's good to have you back man...I hope things are going well.

I would only make one suggestion. Including a quick reference for susp. novices...on what spring rates are and why diffecences are significant.

This is a FAQ if I've ever seen one.
great suggestion.........maybe a reference on the significance of properly tuned dampers as well?? ;)
 

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Immature Tough Guy
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5,671 Posts
Discussion Starter #18
009 -2.0 SE- said:
I would only make one suggestion. Including a quick reference for susp. novices...on what spring rates are and why diffecences are significant.
Sunburst03 said:
great suggestion.........maybe a reference on the significance of properly tuned dampers as well?? ;)
Done and done. :D
 

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Endless USA S13 Silvia
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3,084 Posts
nice after thoughts

another thing i think you should add in there is the fact that the JICs actually provide you with OVER 2" of suspension travel in the rear.......which is a) more travel than the stock dampers and b) the only suspension available with that feature

also........you should mention something about the JICs being able to preload the springs independant of the ride height......which is another reason why they cost that much more than a set of Tein SS ;)
 

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Immature Tough Guy
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5,671 Posts
Discussion Starter #20 (Edited)
Sunburst03 said:
nice after thoughts

another thing i think you should add in there is the fact that the JICs actually provide you with OVER 2" of suspension travel in the rear.......which is a) more travel than the stock dampers and b) the only suspension available with that feature

also........you should mention something about the JICs being able to preload the springs independant of the ride height......which is another reason why they cost that much more than a set of Tein SS ;)
Thanks. A lot of what you're suggesting I cover in my b15 suspension writeup on Southern_Shift, of which a link is provided in the post. I really don't want to dwell on one particular product more than another, and my writeup on S_S goes more into the advantages of one over the other. Read into it, I think you'll like what I have to say about your JICs.

http://www.southern-shift.com/forums/viewtopic.php?t=1001
 
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